Method for fabricating a double wall tub shaped capacitor
US5856220A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 8, 1996 |
| Grant date | Jan 5, 1999 |
| Priority date | — |
| Expiry date | Feb 8, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/716
Abstract
A method and structure is described for a DRAM cell having a double wall tub shaped capacitor. The structure of the capacitor has two embodiments: a double wall tub shaped capacitor and a double wall cup shaped capacitor. In a first embodiment for the tub shaped capacitor, the method comprises using two masks to form a tub shaped hole partial through an insulating layer and a concentric contact hole over the source. A polysilicon layer is formed over the insulating layer. Oxide spacers are formed on the sidewalls of the tub shaped hole. The polysilicon layer is patterned to separate adjacent electrodes. Next, a polysilicon inner wall is formed on the spacer sidewalls. The oxide spacers are then removed. The dielectric and top electrode are formed next thus completing the double wall tub shaped capacitor. The second embodiment for forming the cup shaped capacitor comprises forming an insulating layer the substrate surface and forming a photoresist layer with an opening over a source region. The insulating layer is isotropically etched through the opening to form a cup shaped cavity. Next, the insulating layer is anisotropically etch through the opening to form a contact opening expo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.